Will DTC perform directly before or after higher priority interrupt?

Question:

When H8S/2345 has a DTC request from a lower priority interrupt during the processing of higher priority interrupt, does DTC execute immediately, or does the DTC start after the higher priority interrupt ?

Answer:

The DTC starts immediately as it is one of the bus masters, the CPU is also a bus master. Both have precedence for bus access and DTC takes precedence over CPU. Bus master access has priority over interrupts.